Microelectronic packages called hybrids, or multi chip modules, utilize unpackaged semiconductor die. Because of an increased use of hybrids, semiconductor manufacturers are required to supply unpackaged die that have been tested and certified as known good die (KGD). Known good die is a collective term that denotes unpackaged die having the same reliability as the equivalent packaged die.
The need for known good die has led to the development of test apparatus suitable for testing discrete, unpackaged semiconductor die. As an example, test apparatus for conducting burn-in tests for discrete die are disclosed in U.S. Pat. No. 4,899,107 to Corbett et al. and U.S. Pat. No. 5,302,891 to Wood et al., which are assigned to Micron Technology, Inc. Other test apparatus for unpackaged die are disclosed in U.S. Pat. No. 5,123,850 to Elder et al., and U.S. Pat. No. 5,073,117 to Malhi et al., which are assigned to Texas Instruments.
With this type of test apparatus, a non-permanent electrical connection must be made between contact locations on the die, such as bond pads, and external test circuitry associated with the test apparatus. The bond pads provide a connection point for testing the integrated circuitry formed on the die. The test apparatus typically includes some type of interconnect for effecting a temporary electrical connection to the bond pads on the die.
In making this temporary electrical connection, it is desirable to effect a connection that causes as little damage as possible to the bond pad. If the temporary connection to a bond pad damages the pad, the entire die may be rendered as unusable. This is difficult to accomplish because the connection must also produce a low resistance or ohmic contact with the bond pad.
Another important consideration in testing of known good die is the alignment of the contact locations on the die with the corresponding contact structure on the test apparatus. In assembling the die with the test apparatus it is desirable to quickly and efficiently align the contact locations on the die and corresponding contact structures on the test apparatus.